Geometry and Analysis Seminar
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Mon, 17/01/2011 14:15 |
Roger Bielawski (Leeds) |
Geometry and Analysis Seminar  |
L3 |
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Mon, 24/01/2011 14:15 |
Lothar Goettsche (ICTP) |
Geometry and Analysis Seminar |
L3 |
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Mon, 31/01/2011 14:15 |
Oscar Garcia-Prada (CSIC Madrid) |
Geometry and Analysis Seminar |
L3 |
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Mon, 07/02/2011 14:15 |
Jochen Heinloth (Amsterdam) |
Geometry and Analysis Seminar |
L3 |
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Mon, 14/02/2011 14:15 |
William Crawley-Boevey (Leeds) |
Geometry and Analysis Seminar |
L3 |
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Mon, 21/02/2011 14:15 |
Nitin Nitsure (Tata Institute) |
Geometry and Analysis Seminar |
L3 |
| The Harder Narasimhan type (in the sense of Gieseker semistability) of a pure-dimensional coherent sheaf on a projective scheme is known to vary semi-continuously in a flat family, which gives the well-known Harder Narasimhan stratification of the parameter scheme of the family, by locally closed subsets. We show that each stratum can be endowed with a natural structure of a locally closed subscheme of the parameter scheme, which enjoys an appropriate universal property. As an application, we deduce that pure-dimensional coherent sheaves of any given Harder Narasimhan type form an Artin algebraic stack. As another application - jointly with L. Brambila-Paz and O. Mata - we describe moduli schemes for certain rank 2 unstable vector bundles on a smooth projective curve, fixing some numerical data. | |||
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Mon, 28/02/2011 14:15 |
Geometry and Analysis Seminar |
L3 | |
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Mon, 07/03/2011 14:15 |
Klaus Hulek (Hanover) |
Geometry and Analysis Seminar |
L3 |
| We shall discuss the moduli problem for irreducible holomorphic symplectic manifolds. If these manifolds are equipped with a polarization (an ample line bundle), then they are parametrized by (coarse) moduli spaces. We shall relate these moduli spaces to arithmetic quotients of type IV domains and discuss when they are rational or not. This is joint work with V.Gritsenko and G.K.Sankaran. | |||
